R: [AMPS] RF Choke Forms

[Ian White, G3SEK]

measures wrote:
>>
>>At 09:22 AM 1/15/00 -0700, measures wrote:
>>
>>>When Teflon burns it sublimates into phosgene gas.  (CoCl2)
>>>
>>>cheers, Mauri
>>>
>>>-  Rich...
>>
>>Sure does. Therefor one should never cut Teflon with an acetylene torch
>>unless one wears mil-spec chemical warfare apparel.
>>
>At Raytheon, we had a lathe operator drop dead while turning down a piece 
>of Teflon.  
>


Teflon contains only carbon and fluorine. It is highly stable and will
not burn on its own. One of the decomposition products when it's heated
to flame temperatures in (moist) air is hydrogen fluoride (HF) which is
indeed highly toxic, but you have to keep the teflon exposed to an open
flame and then inhale the smoke.

The only way to drop dead from machining teflon is to make dust in the
air, and draw it through the glowing tip of a cigarette. Even then, I
doubt if it's an immediate death sentence for people with a healthy
heart and lungs. On the other hand, someone who habitually smokes at the
lathe may already have some history...

Phosgene (COCl2) is something completely different, though about equally
unpleasant. It can be made accidentally by drawing the vapour of
chlorinated hydrocarbon solvents through a cigarette, or by exposing the
vapour to electrical arcs or unfiltered UV radiation from a mercury arc
lamp. (Ammonia + household bleach gives plain old chlorine, Cl2)

Phosgene smells of acutely rotten apples. HF doesn't really smell, it's
more a smarting pain in the nose and throat. You can smell both of them
at very low levels, low enough to give a warning that something's wrong. 
Been there, done that, still here...

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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